Welding is a process that uses electric current to overheat and melt the metal, so that the operator can join two pieces together. There are many techniques, but the ones that are used the most at home are MIG welding (M.etal-arc THEnert G.as) and the coated electrode. Although it may seem like a complicated process, it is actually a simple job once you have taken all the safety precautions and gained some practice with the welding machine.
Steps
Method 1 of 4: Ensure Security
Step 1. Purchase a welding helmet
The sparks and light that are emitted during the process are very intense and can damage the eyes; there is also the risk that metal fragments or sparks can reach the face. Purchase a self-darkening helmet or mask online or at the hardware store to protect your eyes and face from the heat and sparks generated by the welding machine.
Step 2. Get a pair of heavy work gloves
You can buy welder-specific ones in hardware stores or online stores; typically, they are made with cow or pig leather and protect the hands from electric shock, heat and radiation. Always wear them when you sell something.
Step 3. Put on a leather apron
This simple device prevents the sparks emitted during the process from coming into contact with the clothes, with the risk of burning yourself; purchase a durable, fireproof one at your hardware store or online retailer.
Step 4. Work in a well-ventilated space
Welding contaminates the air with harmful vapors and gases, so you must proceed outdoors or in a room with open doors and windows.
Method 2 of 4: Prepare the Metal
Step 1. Scrape any rust off the metal before welding
Use 80-grit sandpaper or an angle grinder with a flap disc to treat the entire painted surface of the metal. You can buy the sandpaper or rent the grinder in hardware or online. Continue to sand the metal until it is shiny and its natural color.
Paint and rust prevent the electrical connection generated by the welding machine
Step 2. Rub the metal with acetone
The surface must be free of dust, dirt or residues because any foreign material can alter the quality of the weld; wet a rag with the solvent and rub it on the entire area to be welded. The acetone should dissolve any contaminants that might interfere with the job.
Step 3. Dry it with a clean rag
Rub the metal to remove any traces of solvent left after washing; wait until the surface is completely dry before welding.
Method 3 of 4: MIG welding
Step 1. Verify that the machine is set up correctly
Make sure there is wire on the reel. Look at the tip of the torch to make sure it is fed correctly with the wire; check that the shielding gas nozzle is properly seated and that the machine is operating correctly.
Step 2. Secure the ground clamp to the work table
The machine should be equipped with this cable, which must be connected to the plane on which you intend to weld; by doing so, you do not risk being electrocuted if you touch the table itself.
Step 3. Hold the flashlight with both hands
Place one hand on the work table and use it to control the direction of the torch during welding; the other should grasp the handle with the index finger ready to pull the trigger.
Remember to wear gloves when handling the welding machine
Step 4. Tilt the tip of the flashlight 20 °
Make sure that it maintains this inclination while you place it on the metal you have to weld, in order to facilitate penetration into the surface; some people refer to this position as "pushing".
Step 5. Turn on the machine and pull the trigger
Lower the protective mask and activate the flashlight by creating a bright spark on its tip; keep your face away from the welding area to avoid injuring yourself or breathing toxic vapors.
Step 6. Slowly move the torch over the metal to create the weld
Press the tip to the surface, sparks should be generated; leave it on a single spot for 1-2 seconds before you start moving it.
Step 7. Make small circles as you weld
Continue in this way along the entire surface with circular movements; you should notice that the red-hot material begins to melt behind the tip. When you have reached the end of the welding line, release the trigger and turn off the machine.
- If you move the flashlight too slowly, you could puncture the metal.
- If you move it too quickly, you don't heat the metal enough to melt it and the weld remains very thin.
Method 4 of 4: Coated Electrode Welding
Step 1. Set the machine to positive direct current
Polarity determines whether you are welding with alternating current (AC) or direct current (DC); in this second case, you can set the device with negative or positive polarity. The positive one allows a great penetration force and is the one you should use when taking your first steps in the world of welding.
- AC settings are used when the power source generates only alternating current.
- The negative polarity of the direct current allows less penetration and is used to weld thin metal plates.
Step 2. Set the current intensity
Consult the user manual or the instructions on the packaging of the electrodes you want to use; both should report the current intensity value based on the material they are intended for. Use the adjustment knob on the machine to set this value.
The most common electrodes for steel welding are 6010, 6011 and 6013
Step 3. Connect the ground to the work surface
Take the relative clamp and clip it to the table to avoid being electrocuted while you weld.
Step 4. Insert the electrode into the welding gun
Some machines have a simple clamp, others have a more traditional looking gun. Put the electrode in the tip and tighten the latter to keep it firmly in place; if there is a clamp, slide the stick between the jaws and close them.
Step 5. Hold the gun with both hands
This way, you do more precise work and are able to define straight lines; grab the grip with your dominant hand and use the other as a lower support.
Step 6. Hit the metal with the electrode
Tap it lightly, sparks should be generated. The stick works more or less like a lighter, there must be friction in order to generate the current arc; when you see the sparks and hear the noise, you have started welding successfully.
Step 7. Make a straight line
Slowly move the electrode along the metal plate; as you go you should see that the material melts just behind the tip. The line should be the same size as the weld, with an ideal thickness of about 12mm.
Step 8. Touch the metal for 1-2 seconds to create a weld spot
When you lift the electrode, you open the circuit and stop the development of sparks; this technique allows you to create a circular weld point, very useful when you need to quickly join some pieces of metal.
Step 9. Break the slag with a hammer
After creating the weld, the metal covers it as if it were a shell. This material is called "slag" and is hot; tap it gently with a hammer until it comes off and flakes off.
Do not apply excessive force, otherwise the hot fragments could spread into the air
Step 10. Clean the slag from the weld with a wire brush
Rub it along the joining surface making sure there is no residue left.
